- Surface grafted hyper-branched polyglycerol stabilized Ag and AuNPs heterogeneous catalysts for efficient reduction of Congo Red
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Six types of insoluble polymer-supported beads immobilized with Ag and AuNPs nanoparticle catalysts were synthesized using newly prepared three different types of polymer-supported poly(styrene)-co-poly(vinyl benzene chloride) matrix (PS-PVBC), surface grafted with (i) triethanolamine (TEA), (ii) glycidyl trimethyl ammonium chloride (GTMAC) and (iii) hyper-branched polyglycerol (HPG) and Ag and AuNPs as a catalytic moiety and thus yield polymer-supported nanoparticle catalysts viz., PS-PVBC-TEA-AgNPs and AuNPs, PS-PVBC-g-GTMAC-AgNPs and AuNPs and PS-PVBC-g-GTMAC-AgNPs and AuNPs catalyst respectively. These bead-shaped heterogonous nanoparticle catalysts were characterized by UV-Vis, FTIR, FESEM, HRTEM and TGA techniques. The efficiency for stabilization/loading of metal nanoparticles with respect to varied intensities of hyper-branched chain grafted onto their matrix was screened by determining their comparative catalytic activity. The catalytic potential of thse catalysts was inspected through reduction of Congo Red (CR) keeping pseudo first order identical reaction condition. The observed kobs values reveal that irrespective of metal the catalyst derived from hyper-branched polyglycerol as stabilizing agent viz., PS-PVBC-g-HPG-AgNPs and PS-PVBC-g-HPG-AuNPs shows (kobs = 3.98× 10-2 min-1 and kobs = 4.54 × 10-2 min-1) four and two times greater activity than the catalyst derived from TEA and GTMAC hyper-branched chain. Further, for the same reaction PS-PVBC-g-HPG-AuNPs showed more efficiency than the PS-PVBC-g-HPG AgNPs catalyst. The stability and reusability of the superior catalyst viz., PS-PVBC-g-HPG-AuNPs catalyst was observed to be good even at the sixth cycle. This catalyst can be continuously used to conduct the reduction of various dyes in continuous mode operation in industrial scale.
- Murugan, Eagambaram,Shanmugam, Paramasivam
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- Cu/CuxS-Embedded N,S-Doped Porous Carbon Derived in Situ from a MOF Designed for Efficient Catalysis
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The reasonable design of the precursor of a carbon-based nanocatalyst is an important pathway to improve catalytic performance. In this study, a simple solvothermal method was used to synthesize [Cu(TPT)(2,5-tdc)] ? 2H2O (Cu-MOF), which contains N and S atoms, in one step. Further in-situ carbonization of the Cu-MOF as the precursor was used to synthesize Cu/CuxS-embedded N,S-doped porous carbon (Cu/CuxS/NSC) composites. The catalytic activities of the prepared Cu/CuxS/NSC were investigated through catalytic reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). The results show that the designed Cu/CuxS/NSC has exceptional catalytic activity and recycling stability, with a reaction rate constant of 0.0256 s?1, and the conversion rate still exceeds 90 % after 15 cycles. Meanwhile, the efficient catalytic reduction of dyes (CR, MO, MB and RhB) confirmed its versatility. Finally, the active sites of the Cu/CuxS/NSC catalysts were analyzed, and a possible multicomponent synergistic catalytic mechanism was proposed.
- Wang, Dongsheng,Fan, Mingyue,He, Tingyu,Zeng, Fanming,Hu, Xiaoli,Li, Chun,Su, Zhongmin
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- Graphene oxide nanocomposite magnetic microbeads for the remediation of positively charged aromatic compounds
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Integrating graphene as an inorganic nanostructure within a hydrogel matrix enables the creation of a unique hybrid composite combining the peculiar chemical and physical properties of graphene with the high porosity and stability of hydrogels as for example agarose gel. As a consequence, the resulting material forms a double-network system providing advantages deriving from both the components. In this study, we present the synthesis of novel magnetic porous agarose-based graphene oxide microbeads for the adsorption and separation of positively charged aromatic molecules. The hydrogel-based graphene oxide beads revealed an ultrafast adsorption kinetics for positively charged aromatic dyes. We tested this material for the purification of fluorescent-tagged biomolecules. In addition, reduced graphene oxide microbeads were decorated with palladium nanoparticles, showing a high catalytic activity towards the reduction of dyes by sodium borohydride. Our results show that magnetic agarose based graphene microbeads with enhanced physical-chemical properties can be used for several biochemical applications.
- Clamer, M.,Dalla Serra, M.,Micheli, V.,Minati, L.,Speranza, G.
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- A rationally designed fluorescence chemosensor for on-site monitoring of carbon monoxide in air
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A fluorescence chemsensor for carbon monoxide (CO), based on transformation of weakly fluorescent iodide to strong fluorescent amino product upon reacting with CO, shows abilities of quantitative measurement of CO in air at a level of 50-1000 ppm and real-time and on-site monitoring for CO flammation/explosion.
- Yan, Tengfei,Chen, Jin,Wu, Song,Mao, Zhiqiang,Liu, Zhihong
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- Energy and environmental applications of ultrasonically sulfur doped copper-nickel hydroxides with heterostructures
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A series of sulfur doped copper-nickel hydroxides with heterojunctions were successfully fabricated on nickel foam by adjusting thiourea volume via a facile sonochemical pathway. The effect of volume of thiourea on the final morphology and chemical composition of the hybrids were also investigated by field-emission scanning electron microscopy, and X-ray photoelectron spectroscopy analyses. Furthermore, the electrochemical performance and catalytic activity of the as-obtained hybrids were also investigated. Among the tested electrode, the hybrid material fabricated using 6 ml of thiourea (TU-6) showed outstanding electrochemical properties comprising a high specific capacitance of about 2708 F g?1 at 5 A g?1. In addition, the TU-6 hybrid (catalyst) material displayed remarkable reductive degradation ability towards azo dyes viz., methyl orange (within 8 min) and congo red (within 20 min) in the presence of sodium borohydride (reducing agent) with fast kinetics and good reproducibility, respectively. The exceptional electrochemical performance and excellent catalytic activity of TU-6 hybrid electrode may be attributed to the formation of catalytically active sulfur doped copper-nickel hydroxides (CuS/Ni3S2/NiOOH) three-interface synergistic effect, and unique porous micro-rosette-like texture which increased the diffusion rate and adsorption capacity. The adopted strategy is a simple and generic way for material fabrication to solve the energy and environmental problems.
- Karthik, Namachivayam,Edison, Thomas Nesakumar Jebakumar Immanuel,Atchudan, Raji,Sethuraman, Mathur Gopalakrishnan
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supporting information
p. 126 - 136
(2017/09/22)
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- Method for synthesizing 1-naphthylamine-4-sodium sulfonate by gas-phase SO3 sulfonation method
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The invention relates to a method for synthesizing 1-naphthylamine-4-sodium sulfonate by a gas-phase SO3 sulfonation method. The method is characterized in that gas SO3 and dry air are mixed and cooled, a mixture is introduced into a reaction vessel filled with 1-naphthylamine and an organic solvent for sulfonation, the reaction vessel is heated to the temperature of 160-190 DEG C for transposition, water and solid alkali are slowly added in the reaction vessel for neutralizing until the pH value is 7-9, and the material is subjected to standing and layering to obtain an oil phase and a water phase; the water phase is concentrated until the concentrate proportion is 1.20-1.22, the obtained concentrate is subjected to standing for 1-2 hours at the temperature of 60-80 DEG C, and then the material is separated to obtain the product 1-naphthylamine-4-sodium sulfonate. The method has the advantages of short reaction time, low energy consumption, high efficiency during the reaction process, and no three-waste generation.
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Paragraph 0012; 0013; 0014; 0015; 0016; 0017
(2017/05/02)
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- Efficient degradation of azo dyes using Ag and Au nanoparticles stabilized on graphene oxide functionalized with PAMAM dendrimers
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Herein, we report the stabilization of silver and gold nanoparticles (Ag/Au NPs) on graphene oxide (GO) functionalized with PAMAM dendrimers. The grafting of the PAMAM dendrimers on GO has been investigated using TGA and Raman spectral studies and the stabilization of the Ag/Au NPs on the dendritic structures has been confirmed using XRD, UV-Vis and FT-IR spectra, SEM and TEM studies. The catalytic activity of the prepared nanocatalysts towards the degradation of organic azo dyes, namely methyl orange and congo red, has been tested. The prepared nanocatalysts were found to exhibit excellent catalytic activity towards the complete degradation of both methyl orange and congo red within only a few seconds.
- Rajesh, Rajendiran,Kumar, S. Senthil,Venkatesan, Rengarajan
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supporting information
p. 1551 - 1558
(2014/05/06)
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- BICYCLIC DERIVATIVES AS MODULATORS OF VOLTAGE GATED ION CHANNELS
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Bicyclic derivatives useful as ion channel antagonists are disclosed herein. The compositions thereof are useful for treating or relieving pain-related conditions.
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Page/Page column 50
(2008/06/13)
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